Pressure responsive electric switches



y 1967 c. QUATREDEN IERS 3,319,024 I PRESSURE RESPONSIVE ELECTRIC SWITCHES Filed March 15, 1965 Inventor Gun/0E Qua rema/v/sas JCIRIW M's Atiorney United States Patent ()filice 3,3 19,024 Patented May 9, 1967 3,319,024 PRESSURE RESPONSIVE ELECTRIC SWITCHES Claude Quatredeniers, Les Lilas, France, assignor to General Motors Corporation, a corporation of Delaware Filed Mar. 15, 1965, Se No. 439,755 Claims priority, application Great Britain, Mar. 21, 1964, 12,037/ 64 3 Claims. (Cl. 200-83) This invention relates to pressure responsive electric switches. Such switches are commonly used in internal combustion engines, for example to actuate a warning light in order to indicate whether or not the lubricating oil system is operating below a predetermined pressure.

A pressure responsive electrical switch according to the invention, comprises a cup-shaped conductive body member with an integral tubular boss extending from its .base, a tubular insulator member formed with an internal stepped bore and an external shoulder, an annular disc which abuts the base of the cup portion of the body member, an annular conductive disc which abuts the wider end of the insulator member, a flexible diaphragm the peripheral portion of which is clamped between said annular discs, a movable contact member having a peripheral portion engageable with the conductive annular disc and a central portion which forms a seat for one end of a helical spring the other end of which is seated on a terminal secured in the narrower bore portion of said insulator member, said movable contact member normally being pressed .by said spring into engagement with said annular disc member and with said diaphragm but being disengageable from said annular disc member upon deflection of the diaphragm under pressure applied to the other side thereof, and said cupshaped body member having its rim portion crimped over the external shoulder on said insulator member so as to secure therebetween said annular disc members with the diaphragm clamped therebetween.

The body member is conveniently formed with flats on its external surface for engagement by a spanner or like tool; and its tubular boss is threaded so that it may be screwed into an opening in communication with a source of fluid pressure for actuation of the switch.

In the accompanying drawing the single figure shows a preferred embodiment of a pressure responsive electrical switch according to the invention, the switch being formed from the following eight parts only:

(1) A conductive body member (2) An annular disc (3) A flexible diaphragm (4) An annular fixed contact disc (5) A movable contact member (6) A helical spring (7) An insulator member (8) A connector terminal The conductive body member 1 is formed as a cupshaped metal member 10 with an integral tubular boss 11 extending from the base thereof. The cup-shaped portion 10 is externally of hexagonal shape, so that it may be readily engaged by a spanner or like tool; and the boss 11 is externally threaded.

The insulator member 7 is similarly formed as a cupshaped member 12 with an integral tubular boss 14 and has a stepped axial bore 15 therethrough.

The cup-shaped portion 12 of the insulator 7 fits within the cup-shaped portion 10 of the body member 1; and the flexible diaphragm 3, of synthetic rubber or like material, is clamped at its periphery between the annular disc 2, which abuts the base of the cup portion 10 of the body member 1, and the annular fixed contact disc 4, which abuts the rim of the cup portion 14 of the insulator member 7.

The rim of the cup-shaped portion 10 of the body member 1 is crimped over on to the external shoulder formed by the cup shaped portion 12 of the insulator member 7, as shown at 16, so as to secure the disc members 2, 4 with the diaphragm 3 clamped therebetween.

The connector terminal 8 is secured in the end of the narrower portion of the stepped bore 15 in the insulator 7; and one end of the helical spring 6 abuts the inner end of the terminal 8. The other end of the spring 6 abuts one side of the smaller diameter portion 17 of the movable contact member 5, which is formed as a stepped cup the base of the larger diameter portion 1 8 of which is normally pressed by the spring 6 into contact with the fixed contact disc 4. The smaller diameter portion 17 of the movable contact member 5 is also pressed by the spring 6 into engagement with the diaphragm 3.

In use, the threaded end 11 of the switch is screwed into an opening which is in communication with a. source of fluid pressure, for example the lubrication system of an internal combustion engine, and the terminal 8 is connected in circuit with a battery and an indicator such as a warning light. When the pressure on the diaphragm 3 exceeds that required to move the diaphragm against the pressure of the spring 6 and disengage the movable contact 5 from the fixed contact member 4 the circuit is interrupted and the light extinguished.

A switch according to the invention has a small number of parts which are of simple construction and can be easily assembled.

I claim:

1. A pressure responsive electrical switch according to the invention, comprises a cup-shaped conductive body member with an integral tubular boss extending from its base, a tubular insulator member formed with an internal stepped bore and an external shoulder having an end face, an annular disc which directly abuts the base of the cup portion of the body member, an annular conductive disc which directly abuts said end face of said insulator member, a flexible diaphragm the peripheral portion of which is clamped between and in engagement with said annular discs, a movable contact member having a peripheral portion engageable with the conductive annular disc and a central portion which forms a seat for one end of a helical spring the other end of which is seated on a terminal secured in the narrower bore portion of said insulator member, said movable contact member normally being pressed by said spring into engagement with said annular disc member and with said diaphragm 'but being disengageable from said annular disc member upon deflection of the diaphragm under pressure applied to the other side thereof, and said cupshaped body member having its rim portion crimped over into engagement with the external shoulder on said insulator member so as to secure between said insulator member and said body member said annular disc members with the diaphragm clamped therebetween.

2. A switch according to claim 1, in which said body member is formed with flats on its external surface for engagement by a tool.

3. A switch according to claim 2, in which said tubular boss is threaded so that it may be screwed into an opening in communication with a source of fluid pressure for actuation of the switch.

References Cited by the Examiner FOREIGN PATENTS 9/1962 France.

9/1962 France.

BERNARD A. GILHEANY, Primary Examiner. 10 H. B. GILSON, G. MAIER, Assistant Examiners. 

1. A PRESSURE RESPONSIVE ELECTRICAL SWITCH ACCORDING TO THE INVENTION, COMPRISES A CUP-SHAPED CONDUCTIVE BODY MEMBER WITH AN INTEGRAL TUBULAR BOSS EXTENDING FROM ITS BASE, A TUBULAR INSULATOR MEMBER FORMED WITH AN INTERNAL STEPPED BORE AND AN EXTERNAL SHOULDER HAVING AN END FACE, AN ANNULAR DISC WHICH DIRECTLY ABUTS THE BASE OF THE CUP PORTION OF THE BODY MEMBER, AN ANNULAR CONDUCTIVE DISC WHICH DIRECTLY ABUTS SAID END FACE OF SAID INSULATOR MEMBER, A FLEXIBLE DIAPHRAGM THE PERIPHERAL PORTION OF WHICH IS CLAMPED BETWEEN AND IN ENGAGEMENT WITH SAID ANNULAR DISCS, A MOVABLE CONTACT MEMBER HAVING A PERIPHERAL PORTION ENGAGEABLE WITH THE CONDUCTIVE ANNULAR DISC AND A CENTRAL PORTION WHICH FORMS A SEAT FOR ONE END OF A HELICAL SPRING THE OTHER END OF WHICH IS SEATED ON A TERMINAL SECURED IN THE NARROWER BORE PORTION OF SAID INSULATOR MEMBER, SAID MOVABLE CONTACT MEMBER NORMALLY BEING PRESSED BY SAID SPRING INTO ENGAGEMENT WITH SAID ANNULAR DISC MEMBER AND WITH SAID DIAPHRAGM BUT BEING DISENGAGEABLE FROM SAID ANNULAR DISC MEMBER UPON DEFLECTION OF THE DIAPHRAGM UNDER PRESSURE APPLIED TO THE OTHER SIDE THEREOF, AND SAID CUPSHAPED BODY MEMBER HAVING ITS RIM PORTION CRIMPED OVER INTO ENGAGEMENT WITH THE EXTERNAL SHOULDER ON SAID INSULATOR MEMBER SO AS TO SECURE BETWEEN SAID INSULATOR MEMBER AND SAID BODY MEMBER SAID ANNULAR DISC MEMBERS WITH THE DIAPHRAGM CLAMPED THEREBETWEEN. 